Along the whole Brunlanes coast and the Tjølling coast, melting water from ice formations have made potholes. These are cavities, which appear to have been drilled in the surrounding rocks by eddying currents of water bearing stones and gravel.
Potholes vary in size from a few inches to several feet in depth and diameter. They most commonly occur in shields, where there are ancient rocks, like granite, with different resistance to erosion, so strong pebbles can fall into small cavities in stream bottoms and swirl, making the cavities wider and deeper.
The etymology of Norwegian word “jette” is “giant”.